Understanding factors associated with physical activity (PA) is important to promote PA. The purpose of the present study was to investigate factors associated with achieving PA guideline in 293 Japanese adolescents (140 boys and 153 girls). Time spent in moderate to vigorous PA (MVPA) was accessed by using accelerometers. Based on MVPA, the participants were classified as “Active” (≥60 min/day of MVPA) or “Inactive” (<60 min/day of MVPA). Anthropometry, age, screen time, mental health, participation in after-school sport activities, sleep status, and breakfast status were measured as factors potentially associated with achieving PA guideline. Adjusted logistic regression analyses revealed that after-school sports activities were positively associated with the probability of being Active for both sexes (odds ratios [ORs] [95% confidence intervals (CI)] = 3.90 [1.13-13.49] for boys, 4.80 [1.80-12.81] for girls). In addition, body fat was negatively associated with a reduced likelihood of being Active for girls (ORs [95%CI] = 0.93 [0.87-0.97]). Two factor ANOVA revealed that those in Inactive group had significantly lower PA levels than those in Active group on both regular curriculum and extra-curriculum (F _{(1, 138)} = 152.50 for boys, F _{(1, 151)} = 181.95 for girls, p < 0.001). In addition, for girls, there was a significant interaction effect between domain (regular curriculum vs. extra-curriculum) and after-school sport activities (F _{(1, 151)} = 4.91, p = 0.028), suggesting that obtaining higher PA levels on extra-curriculum might be difficult for those who do not belong to any after-school sport activities. Therefore, promoting PA on regular curriculum (i.e., physical education lessons and recess) might be alternative ways to increase PA levels for those individuals. Furthermore, special attention may be needed for girls who have higher body fat to promote PA.

The purpose of the present study was to examine the associations between physical fitness and body fatness with blood lipid profile in 231 Japanese children and adolescents (12.1 ± 1.5 years). The primary outcomes of the present study were a lipid risk score which was calculated by summing up z scores of three lipid items (triglycerides, low density lipoprotein-cholesterol, and high density lipoprotein-cholesterol). Physical fitness was assessed by using the Japanese standardised fitness test. For body fatness, a percentage of overweight was calculated with using age-, sex-, height-specific standardised body mass. For combined analysis (fitness × fatness), the participants were cross-tabulated into four groups (Non-Obese/Higher-Fit, Non-Obese/Lower-Fit, Obese/Higher-Fit, and Obese/Lower-Fit). The results demonstrated that the participants in fitness categories A/B [most fit] and C [middle] demonstrated the lower (better) lipid risk score than the participants in fitness categories D/E [least fit] (F _{(2, 222)} = 6.03, p = .003). For body fatness, the lipid risk score in obese group was significantly higher (worse) than that in thin and normal groups (F _{(2, 222)} = 6.08, p = .004). The combined analysis showed that there was a significant interaction (fitness × fatness) on the lipid risk score (F _{(1, 221)} = 4.05, p = .047), suggesting that Obese/Lower-Fit group had the worst risk score compared to the other groups. The present study suggests that improving both fitness and body fatness might be important for better lipid profile in Japanese children and adolescents.

Limited evidence was available to support the effect of self-selected activities performed under free-living conditions on postprandial lipaemia, particularly for older adults. Thus, the aim of the present study was to examine the chronic effect of increased physical activity of daily living on postprandial triacylglycerol (TAG) in postmenopausal women. Twenty-eight postmenopausal women, aged 71 ± 4 years (mean ± SD), were randomly divided into two groups: active (n=14) and control (n=14) groups. The participants in the active group were asked to increase their activities above their usual lifestyle levels for 4 weeks; freely deciding the duration and intensity of their chosen activities. The participants in the control group maintained their usual lifestyle for 4 weeks. All participants were asked to wear a uniaxial accelerometer for 4 consecutive weeks. At baseline and after 4 weeks, all participants rested and consumed a standardised breakfast and lunch after a 24-h period of physical activity avoidance. Blood samples were collected in the fasted state (0 h) and at 2, 4 and 6 h after breakfast. After 4 weeks, the participants in the active group increased their step counts by 600 steps/day (from 6979 ± 2057 to 7586 ± 2301 steps/day, p=0.047). There was no difference in the pattern of postprandial TAG response between groups (trial × time interaction, p=0.335). A previous study has suggested that only recent exercise (i.e., 12h before but not 24 h before) appears to facilitate the exercise-induced postprandial TAG lowering effects. Thus, in the present study, postprandial lipaemia was not reduced after performing self-selected activities under free-living in postmenopausal women.